Hydraulic gear



Jan. 20,192 1,523,834

G. W. PARR HYDRAULIC GEAR I Filed March 21. 1924 2 Sheets-Sheet 1 Jan. 1925- 1,523,834

G. w. PARR HYDRAULIC GEAR rch 21, 1924 2 Sheets-Sheet 2 llll 5 o T w o i l' Jan. 2%, I925.

G-EQFFREY WARNER PAIR/R, OF LONDON, ENG-LAND.

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Application filed March 21,

To all whom it may concern:

Be it known that I, GEOFFREY WARNER Paint, a British subject, and resident of Loampit Hill House, Iiewisham, London, S. E. 13, England, have invented certain new and useful Improvements in Hydraulic Gears (for which I have filed application in Great Britain December 22, 1922), of which the following is a specification, such as will enable, others skilled in the art to which it appertains to make and use the same. I

This invention relates to improvements in rotary hydraulic change speed mechanism of that kind in which a plurality of cylinders and pistons or like devices are employed in two groups both groups of cylinders being connected to a driving member and one group of pistons being connected to the driven member and the other to a nonrotating member, and in which change in relative speed between the two elements is obtained by altering the position of the non-rotating member relatively to the driving member.

In change speed'gear of this type it has been suggested vpreviously to. control the position of a variable throw eccentric, mounted on an eccentric portion of a nonrotating member, by means of worm gearing, whilst the valves of the separate groups of cylinders were operated from eccentrics mounted on the driven shaft and adapted to be relatively adjusted thereon. In an arrangement where swash plates were used.

it has been suggested to vary the position of the non-rotating swash plate by hydraulic means comprising cylinders whose pistons were connected to diametrically opposite points of the non-rotating swash plate, and a pump for producing the flow of the liquid.

According to the present invention, valves appertaining. to the cylinders whose pis tons or the like are connected to the non-rotating member are operated by a fixed cam, eccentric or the like. The position of the non-rotating member is controlled by the operation of two spring-controlled valves so arranged that when one of the valves is opened oil or other liquid will escape from a cylinder controlled by that valve allowing the non-rotating member to move in one direction only, under the influence of the 1924. Serial No.; 700,9i6.

alternating load applied by the rotating 55 pistons or the like running on said nonrotatmg member. These valves preferably control two opposed closed ended cylinders having a common piston, the centre portion of the piston forming a cross head connected to the non-rotating member, the arrangement being such that when one of the valves is opened the interiors of the cylinders are brought into communication so that the oil can flow from one to the other allowing es the piston to move one way or the otheraccording to the valve which has been opened and thus vary the position of the non-rotating member. a

The functions of the pistons and their as- 7 sociated cylinders may be performed by oscillating telescoping tubes, in which 'case the oscillations of these tubes are utilized to operate valves controlling the flow of into or out of the telescopic tubes is controlled by balanced poppet valves operated by rocking tappets controlled either by the oscillations of the. telescopic tubes or by other means. v

The non-rotating member is capable of adjustment in two directions from the osition it occupies at direct drive, in one direction to obtain the predetermined maximum the oil or other liquid. The flow of oil high forward speed, and in the other di- 35 rection, from the same position, to obtain a smaller forward speed and any prede' termined reverse speed with a neutral position between forward drive and reverse.

I will now describe my invention with reference to the accompanying drawings in which:

Fig. 1 is a vertical section on line lD-D of Fig. 2, of a form in which the cylinders are radial to the axis, and Fig. 2 is a horizontal section on line AA of Fig. 1.

Fig. 3 is a vertical section through the control gear on the line C-C of Fig. 4

which is a part vertical section on line BB of Fig. 3.

Referring to Figs. 1, 2, 3 and 4, these show a radial form of the invention, particularly applicable to the transmission gear of motor cars, the rotor being mounted direct on the crank shaft of the engine and forming the "fly wheel thereof.

In this form the'rotor a is mounted on the plate b which is bolted to the driving shaft 0 and forms the fly wheel of a motor, of which 0 is the driving end of the crankshaft.

The driven shaft pl has formed on its end the eccentric E which runs on a roller hearing 6 mounted on the end of the driving shaft 0.

A variable throw eccentric E is mounted on a slide f sliding on a member carried by the case 9 and is controlled as to position by the oil cylinders h and pistons i. Mounted in the rotor at are detachable abutments j and lying between each of these abutments and one or other of the eccentrics E- and E is an oil column K or K the columns marked K bearing on the driven eccentric E and those marked K on the nonrotatable eccentric E These columns are contained within telescopic tubes, consisting of two members} and m slidingone .within the other.

It will be seen that these oil columns and their containing tubes form in effect oscillating cylinder and piston pairs, the curved faces of the abutments j acting as pivots about which the columns and tubes can.

swing. They have the advantage over simple oscillating cylinders, however. that as the load is taken directly by the oil there is no appreciable pressure between metallic parts, all friction being fluid friction and therefore sensibly independent of load.

Carried in holes bored in the rotor a are balanced poppet valves n whose purpose is to put the oil columns into communication with either one or the other of two tubes A and B carried by the rotor. Those valves controlling, the K columns, that is, those columns bearing on the eccentric E are operated by swinging tappets 0 carried by the abutments j and engaging at one end with the heads of the valves and at the other with the inner members Z of the oil column containing tubes, so that as the tubes oscillate from side to side the tappets are caused to swing and so operate the valves.

The valvescontrolling the-K columns, that is, those columns bearing on the non"- rOtatabIe eccentric E'f, are operated by cams p, which are carried by squared shafts (,1. These shafts have arms r-pinned on their other, ends and these arms carry rollers s which run in an eccentric track t formed in the case 9, the arrangement being such that as the rotor revolves within the case the rolls 8 running in the eccentric track cause the arms r to oscillate, and-with them the shafts g and the cams p, the oscillations of these cams operating the valves in the same mannor. that the-swinging tappets 0 operate the valves of theK group.

Leaving the control gear to be described later, the mechanism operates substantially as follows a The K group of'oil columns together with Leeaesi their associated telescopic tubes, abutments and valves form, with the non-rotatable eccentric E an oil pump, pumping oil from one to the other of the two tubes A and B. In the same way the K group and its asso ciated parts form an oil motor, driven by the oil pumped by the pump group K and driving the driven eccentric E It will be readlly understood that the amount of oil pumped per revolution of the rotor is proportional to the throw of the nonrotatable eccentric E and that the direction in which it is pumped will depend on which side of the centre line the eccentric lies; moving it over from one side to the other of the centre line will reverse the direction in which the oil is pumped.

It will also be understood that the speed at which the driven eccentric E is driven by the motor group K depends on the rate at which oil is pumped by the pump group K and that the direction in which it is driven relatively to the rotor will depend on the direction in which the oil is being pumped. It will therefore be seen that both the direction and speed of the driven eccentric relatively to the rotor is controlled by the position in which the non-rotatable eccentric E is set; if the fixed eccentric is set on that side of the centre line which causes oil to be pumped in such a direction that the driven eccentric is caused to rotate in the opposite direction to the rotor, the driven eccentric will rotate more slowly than the rotor, so that the mechanism will gear down, and if it is set on the opposite side, so that the driven eccentric is caused to rotate in the same direction as the rotor, then the driven eccentric will rotate faster than the rotor, so that the mechanism will gear up.

If the non-rotatable eccentric is set in such a position that the driven eccentric is caused to rotate backwards at the same speed that the rotor is rotating forwards, then the driven eccentric will be stationary, giving" neutral. and if the throw of the nonrotatable eccentric is then increased so that the driven eccentric is caused to rotate backwards" faster than the rotor is rotating forwards, then the driven eccentric will rotate backwards, giving reverse.

The minimum reverse ratio and the maximum gearing up ratio are fixed by the proportions of the gear, and in the design illustrated in the drawings are 4 to 1 and 2.25 to 1 respectively, so that if the driving shaft 0 is driven at a constant speed of 1000 R. P. M., the speed ofthe driven shaft (Z can be made anything between minus 250 R. P. M. (that is to say, 250 R. P. M. in reverse) through zero to plus 2250 R. P. M. (that is to say, 2250 R. P. M. forward), depending on the position in which the non-rotatable eccentric E is set.

Leeasse m" The method of controlling the position of the non-rotatable eccentric E is much through the medium of the floating lever o, the pistons i and the non-rotatable eccentric E to which they are attached will be free to move in the direction of the cylinder the valve of which is open.

Now as the oil columns K rotate about the eccentric E the oil pressure will tend to move the eccentric first in one direction and then in the other, but as it is only free to move towards the control cylinder whose valve is open, it will move in that direction, but not in the other so that swinging the lever o, by means of control rod w which moves in a slot a formed in the slide f to which the eccentric E is fixed the selected valve may be opened to permit movement of the non-rotatable eccentric in the desired direction. Pinned to the same shaft as lever '0 is another lever y which thus carries the pivot of the floating lever 11, so that as the eccentric slide moves, the system of lovers will close the valve that has been opened by the control rod w. The chamber a is always kept full of oil and the piston that is moving outwards therefore draws in oil from it, its valve lifting automatically against its spring to allow this. The floating lever method of operating the valves is that known as an overtaking gear or follow up and frequently used in hydraulic servomotors, and the whole of the control mechanism acts in much the same manner as a servo-motor, but instead of employing oil under pressure to force the pistons to move, they are allowed to move under the alternating load imposed by the rotating oil columns and the oil is only used to control this. movement.

Instead of the floating lever, any other known or convenient methods of operating servo-motor valves may be used.

1. In a rotary hydraulic change speed mechanism, a driving member, a driven memher, a series of pump elements connected to the driving member, a series of motor elements connected to the driving member, means on the driven member wherebythe notor elements may operate said driven member, means whereby the power of the pump elements may be communicated to the motor elements for operating the latter, and a member for controlling the operation of the pump elements, said member being adjustable by contact with the pump elements to vary the extent and direction of operation :of the pump elements.

2. In a rotary hydraulic change speed mechanism, a driving member, a driven member, a series of pump elements connected to the driving member, a series of motor elements connected to the driving member, means on the driven member whereb the motor elements may operate said riven member, means whereby the power of the pump elements may be communicated to the motor elements for operating the latter, a member for controlling the operation of the pump elements, said member being adjustable by contact with the pump elements to vary the extent and direction of operation of the pump elements, and manually controlled valves to govern the adjusting effect of the pump elements on said control member.

3. In a rotary hydraulic change speed mechanism, a driving member, a driven member, a series of pump elements connected to the driving member, a series or motor elements connected to the driving member, means on the driven member whereby the motor elements may operate said driven member, means whereby the power otthe pump elements may be communicated to the motor elements for o crating the.,latter,

valves for controlling uid admission to the pump elements, a fixed eccentric track for Eperating said valves, valves'for controlling uid admission tothe motorelernents, means actuated in the relative movement of the motor elements as such for controlling said latter valves, and a non-rotatable eccentric for operating the pum elements,said eccentric being adjustable t rough contact wit-h the pump elements.

4. In a rotary hydraulic change speed mechanism, a driving member, a driven member, a series of ump elements connected tothe driving mem er, a series of motor elements connected to the drivin member, means on the driven member w ereby the motor elements may operate said driven member, means whereby the power of the pump elements may be communicated to the motor elements for' operating the latter, a non-rotatable eccentric for operating said pump elements, fluid cylinders for controlling the position of said eccentric, and means to relieve the fluid pressure in either of said cylinders at will to permit the contact cooperation between the pump elements and eccentric to adjust the eccentric to the predetermined degree.

5. Ina rota hydraulic change speed mechanism, a r'ving member, a. driven member, a series of pump elements connected to the driving member, a. series of motor elements connected to the driving member,

means onthe driven member whereb the motor elements may operate said riven member, means whereby the power of the pump elements may be communicated to the 5 for motor elements'for operating the latter, a non-rotatable eccentric for operating said pump elements, fluid cylinders for cont-rolling the position of said eccentric, valves controlling the I fluid pressure in said cylinders, and meansto manually ope-n either of said valves at Will to thereby relieve the fluid pressure in a particular cyl" der to permitsaid eccentric to move towards said cylinder under pressure from the pump elements.

In testimony "whereof I have signed my name to this specification.

GEOFFREY WARNER FARR. 

